To precisely locate a wheel on the hub of certain trucks, locators are provided on the hub which are outwardly projecting studs in parallel relationship with each other and with the axis of the wheel, spaced around the hub and positioned so as to project inside the central opening of a wheel. The hubs may have four, five or six of such locators to accurately position a wheel thereon. The hub assembly of wheels, including the projection of the axle and the locators, tends to collect dirt and oil and generally present an unslightly exterior appearance.
To enhance the exterior appearance of the wheels of trucks, a cap is provided which fits within the central opening of the wheel and covers the portion of the hub visible through the central opening of the wheel, including the locators and the axle. The cap must fit tightly against the hub of the wheel and move in union with the wheel as it rotates and crosses rough terrain so as not to rattle or vibrate and thus cause undesired noises.
The cap is generally concavo-convex in shape with a circular perimeter, and has arcuate flanges spaced around the circular perimeter which project away from the concave side of the cap. The arcuate flanges fit tightly within the central opening of the wheel and extend between the locators to rigidly retain the cap over the hub of the wheel. To maintain the necessary rigidity of the cap on the wheel, it is desirable to maximize the angular lengths of the flanges, and provide rigidity to the flanges.
Existing caps which are designed to fit a four locator hub have four arcuate flanges; caps designed to fit a five locator hub have five arcuate flanges; and caps designed to fit a six locator hub have six arcuate flanges. In each case the flanges are adapted to project inside the circular central opening of a wheel and extend around the inside circumference between the locators on the hub.
Suppliers of caps have been required to maintain expensive inventories and allocate storage space for caps which are substantially the same in appearance, but accommodate each of the three different configurations of locators. Furthermore, truck owners seeking to purchase caps have frequently found themselves confused and frustrated by not knowing the number of locators on their hubs, and therefor risk purchasing unusable caps. It is, therefore, desirable to provide a single cap which would fit securely on hubs having any of the three configurations of locators, and thereby reduce confusion, costs, and storage space, all of which arise from the requirement that separate caps be available for each configuration of hubs.